In recent years, devices referred to as metamaterials have been attracting attention. This metamaterial refers to an artificial substance which has electromagnetic and/or optical properties provided by none of substances in nature. Typical properties of this metamaterial include a negative magnetic permeability (μ<0), a negative dielectric constant (∈<0), or a negative refractive index (when the magnetic permeability and the dielectric constant are both negative). It is to be noted that the region with μ<0 and ∈>0 or the region with μ>0 and ∈<0 is also referred tows a “evanescent solution region”, whereas the region with μ<0 and ∈<0 is also referred to as a “left-handed region”.
Left-handed metamaterials with μ<0 and ∈<0 are made by a periodic arrangement of an element with a negative dielectric constant and an element with a negative magnetic permeability, in order to develop a negative dielectric constant and a negative magnetic permeability at the same time.
Left-handed metamaterials are classified roughly into a circuit system and a resonance system. As a means for developing negative magnetic permeability μ in the resonance system, for example, a split ring resonator (SRR) has been known (for example, see Non-Patent Document 1).
On the other hand, as a means for developing negative dielectric constant ∈, a metallic wire has been known which is sufficiently long with respect to the wavelength of an electromagnetic wave. This metallic wire decreases a plasma frequency to develop negative dielectric constant ∈. Non-Patent Document 2 discloses the ability of an array of metallic wires to develop negative dielectric constant ∈. In addition, Japanese Patent Application Laid-Open No. 2008-507733 (Patent Document 1) discloses a wire of a periodic lattice for a negative dielectric constant.
In addition, it has been also known that a metallic wire which has a length of half the wavelength λ of an electromagnetic wave generates a negative dielectric constant through a resonance with the electromagnetic wave. Further, it has been known that a waveguide exhibits a negative dielectric constant in a frequency band not more than a cutoff frequency.    Patent Document 1: Japanese Patent Application Laid-Open No. 2008-507733    Non-Patent document 1: “Left-handed Metamaterial”, Nikkei Electronics January 2, Nikkei Business Publications, Inc., Jan. 2, 2006, PP. 75-81    Non-Patent document 2: J B Pendry et al., “Low Frequency Plasmons in thin-wire structures”, J. Phys. Condens. Matter Vol. 10 (1998) 4785-4809